The present invention relates to a method of improving the control behavior of an ABS system.
Electronically controlled anti-lock systems (ABS) are state of the art and customary on the market in many different designs. The most important or exclusive input quantity for braking pressure control is the rotational behavior of the individual vehicle wheels which is measured by wheel sensors. A vehicle reference speed is produced by logically combining the measured quantities. The vehicle reference speed is used instead of the actual vehicle speed as a reference quantity to define the wheel slip and other control quantities and, thus, as a reference quantity for braking pressure control during an anti-lock control operation.
It is well known and can be easily observed that the control of an anti-lock system (ABS) responds in some situations although there is no reason for response. One example is the triggering of a control operation by a so-called single disturbance, i.e., by a major road surface disturbance due to a depression or a pothole, a threshold, or the like. If such a disturbance occurs in the partial braking range, i.e., during an uncontrolled braking operation, the effects of the disturbance will at least irritate the driver. Also, the major pressure relief or pressure reduction due to the wheel deceleration results in a reduced deceleration which is disadvantageous.
Therefore, an object of the present invention is to provide an improved control behavior of an ABS system and, more particularly, to suppress the unwanted effects of single disturbances in the road surface.